This invention relates generally to the field of attaching sensors and targets, and more particularly to an apparatus to easily, simply and safely attach and operate motion detector sensors on equipment with rotating shafts.
In the past history of industry, it has always been necessary to determine if certain or all the equipment so pertaining to that particular plant are running. In recent years, many sensors have been developed. One in particular has been the proximity sensor. This sensor senses the presence of metal when a “metal target” comes close to its sensing head. Others are the magnetic reed sensor, capacitance sensor and the hall effect sensor. Most of industry today relies on the proximity sensor because of its standard configuration. It should be noted that the common term associated for all of these sensors are referred to as “motion sensors or motion switches” because the end result of their presence on the equipment is to determine if that particular piece of equipment is running. When mounted and wired on the equipment to be monitored a signal will be generated when the target passes the head of the sensor. This signal is sent to a control room or station where the information is used to alert personnel of the status of the equipment that is being monitored. In other words, the sensor detects motion of the turning shaft.
A proximity sensors that most widely used by industry currently which involves the placement of the sensor on equipment with rotating shafts. First, the shaft of the equipment being monitored needs to have a metal target attached to it. The target's purpose is to provide a presence of metal for the proximity sensor. This is usually accomplished by using a metal rod, key stock, flat bar or other metal and attaching it to the shaft. This is done by either welding or bolting the target to the shaft. Next, the sensor itself has to be mounted on the equipment close to the target that has been attached. This mounting of the sensor can be accomplished by either fabricating or purchasing a holder. The holder needs to be welded or bolted close to the target. Once this is accomplished, the equipment being monitored needs to be started and the sensor is adjusted so when the target on the rotating shaft goes past the head, a signal will be generated by the sensor. Or in other words, the sensor detected motion of the shaft.
Another method of monitoring rotating shaft equipment is by using shaft driven sensors or by using shaft driven sensor holders. The shaft driven sensors, commonly called encoders, need to have an orifice in the end of the rotating shaft of the equipment for the encoder's shaft to be inserted. That is done by drilling and or drilling and taping the shaft of the equipment being monitored. The encoder is then either inserted or screwed in the end of the equipment shaft. Another method of monitoring a rotating shaft is by using proximity sensor holders that have a shaft to rotate a target for the sensor that attaches to the holder. In this case, the shaft of the equipment being monitored needs to be drilled and or drilled and taped for the size of the holder shaft. After this is done, the holder shaft is inserted over or screwed in the equipment shaft.
In reference to all the above, a guard needs to be fabricated or purchased to cover the entire assembly of target, encoder, proximity sensor and proximity sensor holder. This is done for safety reasons.
Other prior art of mounting sensors to rotating shaft contain a similar concept where as a target rotor is attached to a sensor holder with a guard cover. But, unlike the invention here in being described, the problem of installation to the shaft of the equipment that is to be monitored still exists. In these cases, the shaft still needs to be drilled and tapped, coupled, or any means were by the device that holds the sensor and target can be attached to the shaft. These devices are sometimes referred to as a universal mount for sensors, but are not to be considered “self-attaching” as is the invention being discussed.
The deficiency of the prior technology of mounting sensors to rotating shaft equipment is that it takes much time and planning to install. It also takes numerous tools to complete, such as a welder, torches, drills, taps and hardware. It also needs the skills of a burner, welder and metal fabricator.
Further, when the equipment being monitored needs maintenance, such as a shaft bearing needing replaced, all of the mounted parts need to be disassembled. The sensor target needs to be either burnt off with a torch or unbolted from the shaft. The sensor itself will need to be removed from the equipment frame. The universal mounting devices need to be un-coupled from the shaft. Once the bearing is replaced, the entire reassembling and adjustments must be made.
Further deficiency of the prior technology of the installation of sensors and targets would be if a guard were not installed to cover both the sensor and the target. Serious bodily harm would occur. Serious injury could occur if a worker or others garments because entangled by the target that protrudes from the rotating shaft of the equipment being monitored. Also, if a worker or other place a finger close to the sensor head and the target passed in front of the head, a severe pinch point will happen. Even with the universal sensor mounts, there still is a rotating shaft that connects both the device and the equipment shaft. Further deficiencies of the prior technology of installation of sensors are that much planning must be done before the sensor is to be mounted. Holders need to be fabricated or purchased. Targets need to be fabricated. Guards need to fabricated or purchased. Personnel must be available when installation is to start. When this much planning has to happen, something is usually forgotten causing a delay in the installation. Further deficiency of the prior technology of installation of sensors is in the case of universal devices that have a target, guard and sensor mount. These devices need to have the shaft of the equipment being monitored either drilled and tapped or have a special coupler designed to fit over the shaft.